1. Field of the Invention
The present invention relates to an electron emission display and a method of manufacturing the electron emission display, and in particular, to an electron emission display that improves the shape of an anode electrode to reduce or prevent color mixing and to heighten an adhesion of the anode electrode to a black layer, and a method of manufacturing the electron emission display.
2. Description of Related Art
In general, an electron emission element can be classified, depending upon the kind of electron source, into a hot cathode type or a cold cathode type.
Among the cold cathode type of electron emission elements, there are a field emitter array (FEA) type, a surface conduction emission (SCE) type, a metal-insulator-metal (MIM) type, and a metal-insulator-semiconductor (MIS) type.
Arrays of electron emission elements are arranged on a first substrate to form an electron emission device. A light emission unit is formed on a second substrate with phosphor layers and an anode electrode, and is assembled with the first substrate to thereby form an electron emission display.
In the electron emission display, a plurality of driving electrodes functioning as scanning and data electrodes are provided on a first substrate together with electron emission regions, and a light emission unit is provided on a second substrate. The electron emission regions and the driving electrodes are operated to control the on/off of electron emission for respective pixels and also the amount of electrons emitted from the electron emission regions. The electrons emitted from the electron emission regions excite the phosphor layers to thereby emit light or display images.
With the above described electron emission display, a metallic layer based on a metallic material, such as aluminum (Al), may be used as the anode electrode. The metallic anode electrode covers the phosphor layers and black layers, and reflects the visible rays radiated from the phosphor layers to the first substrate back toward the second substrate, thereby heightening the screen luminance.
The phosphor layers are formed by depositing phosphor particles with a particle size of several micrometers (μm), and the anode electrode is formed to be thin with a thickness of several thousands angstroms (Å) in view of the electron transmittance degree. In this situation, when aluminum is directly deposited onto a surface of the phosphor layers, it does not uniformly cover the surface of the phosphor particles and may include areas having no aluminum (e.g., periodic cuts or holes). This makes it difficult to form the anode electrode with a high uniformity.
Accordingly, in order to make the anode electrode more uniformly thick, a surface flattening layer is formed on the phosphor and black layers of the second substrate, and aluminum is deposited onto the surface flattening layer, thereby forming the anode electrode. The surface flattening layer is removed through firing, and after the firing, the anode electrode is spaced away from the phosphor and black layers with a certain (or predetermined) gap. That is, the anode electrode is smoothly deposited onto the surface flattening layer and so the periodic cuts thereof are reduced, thereby also heightening the reflection efficiency.
As the surface flattening layer is formed on the entire surface of the phosphor and black layers, the anode electrode is spaced away even from the non-light emission areas (i.e., the black layers) with a certain (or predetermined) gap. Consequently, when spacers are mounted corresponding to parts of the black layers before the assemblage of the first and second substrates, the anode electrode may be damaged by the spacers.
Furthermore, as the conventional anode electrode covers all the phosphor layers on the second substrate, the visible rays emitted from the different-colored phosphor layers are reflected by (or against) the anode electrode, and mixed, thereby inducing color mixing.